FLUID INCLUSION STUDY OF GYPSUM PRECIPITATED IN ACID SALINE WATERS: PRELIMINARY RESULTS FROM MARS-ANALOG SALAR IGNORADO, NORTHERN CHILE
Abundant bottom-growth gypsum crystals at Salar Ignorado contain fluid inclusions that record environmental conditions in the salar. Petrographic observations with plane transmitted, reflected, and polarized light, and UV-vis epi-fluorescence show that triangular, horn-shaped, and sub-rectangular primary fluid inclusions contain waters, air bubbles, prokaryotes, algae, and organic compounds. Some inclusions with possible cellular material contain micrometer-scale clear, spherical solids. Laser Raman spectroscopy with 532 nm excitation shows that these spherical solids are high molecular weight alkane-rich hydrocarbons with variable fluorescence intensity. Study of extremophile microorganisms and organic compounds from this terrestrial Mars-analog environment, and their style of preservation within the rocks, may lead to improved methods for the search for past life on Mars.